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United States Patent |
6,053,520
|
Wu
|
April 25, 2000
|
Bicycle pedal crank mounting arrangement
Abstract
A bicycle pedal crank mounting arrangement in which two wheel boards are
fixedly fastened to two opposite ends of a bottom bracket bearing axle of
a bicycle, two flat-plate counter weights are respectively fixedly
fastened to the wheel boards at an eccentric location in reversed
directions, and two pedal assemblies are respectively fastened to the
flat-plate counter weights for pedaling by legs to rotate the wheel
boards, the bottom bracket bearing axle and the chain wheel being mounted
on the bottom bracket bearing axle.
Inventors:
|
Wu; Chun-Sheng (14/F., No. 152, Mei-Tsun Rd., Sec. 2, Taichung City, TW)
|
Appl. No.:
|
110480 |
Filed:
|
July 7, 1998 |
Current U.S. Class: |
280/259; 74/594.1; 280/217 |
Intern'l Class: |
B62M 001/99 |
Field of Search: |
280/259,217,260,261
74/594.1,594.2
|
References Cited
U.S. Patent Documents
667053 | Jan., 1901 | Allman | 74/594.
|
709934 | Sep., 1902 | Spence | 74/594.
|
5566589 | Oct., 1996 | Buck | 74/594.
|
5816600 | Oct., 1998 | Matsuura | 280/259.
|
Foreign Patent Documents |
4113833 | Oct., 1992 | DE | 280/259.
|
1699855 | Dec., 1991 | SU | 280/259.
|
Primary Examiner: DePumpo; Daniel G.
Attorney, Agent or Firm: Rosenberg, Klein & Lee
Claims
What the invention claimed is:
1. A bicycle pedal crank mounting arrangement comprising two wheel boards
fixedly fastened to two opposite ends of a bottom bracket bearing axle of
a bicycle, two cranks respectively coupled to said wheel boards, two
pedals respectively mounted on said cranks at one end remote from said
wheel boards and pedaled to rotate said wheel boards and said bottom
bracket bearing axle, wherein two flat-plate counter weights are
respectively fixedly fastened to said wheel boards at an outer side at an
eccentric location in reversed direction; said cranks each have one end
respectively fixedly fastened to said flat-plate counter weights, and an
opposite end respectively connected to said pedals.
2. The bicycle pedal crank mounting arrangement of claim 1 wherein said
flat-plate counter weights each have a coupling hole; said cranks each
have a coupling block respectively plugged into the coupling holes on said
flat-plate counter weights, and a plurality of mounting lugs equiangularly
spaced around the respective coupling block and respectively fastened to
said wheel boards by fastening elements.
Description
BACKGROUND OF THE INVENTION
The present invention relates to bicycles, and more specifically to the
mounting arrangement of the pedal cranks for a bicycle which enables the
user to propel the bicycle efficiently with less effort.
In a regular bicycle, a bottom bracket bearing axle 11' is revolvably
supported in a bottom bracket at the bottom side of the frame 10', a chain
wheel 12' is mounted on one end of the bottom bracket bearing axle 11', a
chain 14' is mounted on the chain wheel 12' and a sprocket wheel 13', and
two pedal assemblies 15' are respectively connected to the ends of the
bottom bracket bearing axle 11'. Each pedal assembly 15' comprises a crank
16' and a pedal 17'. This crank mounting arrangement is not satisfactory
in function. Because the cranks 16' of the pedal assemblies 15' are
respectively fixedly connected to the ends of the bottom bracket bearing
axle 11', the arm of force is limited, and the user must employ much
effort to the pedals 17' when pedaling the pedal assemblies 15'.
SUMMARY OF THE INVENTION
The present invention has been accomplished to provide a bicycle pedal
crank mounting arrangement which enables the user to pedal the pedal
assembly efficiently with less effort. According to one aspect of the
invention, the cranks of the pedal assemblies are symmetrically
eccentrically coupled to two wheel boards at the ends of the bottom
bracket bearing axle. Because the arm of force is relatively increased,
the user can pedal the pedal assemblies to rotate the bottom bracket
bearing axle with less effort. According to another aspect of the present
invention, flat-plate counter weights are fixedly connected between the
wheel boards and the cranks of the pedal assemblies. The flat-plate
counter weight accelerate the speed of rotation of the respective wheel
board when the crank of the respective pedal assembly is turned downwards
from the up stroke to the down stroke.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the arrangement of the chain wheel, the chain, the bottom
bracket bearing axle and the pedal assembly of a conventional bicycle.
FIG. 2 is an exploded view of the present invention.
FIG. 3 is an assembly view of FIG. 2.
FIG. 4 is a plain view of the present invention.
FIG. 5 is a schematic drawing showing the operation of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 2, 3 and 4, a bottom bracket bearing axle 11 is
revolvably mounted in the bottom bracket of a bicycle frame 10, and a
chain wheel 20 is mounted on one end of the bottom bracket bearing axle
11. Two wheel boards 21 are mounted on the ends of the bottom bracket
bearing axle 11. Each wheel board 21 has a center hole 210. Two cap
members 23 are respectively plugged into the center holes 210 on the wheel
boards 21 and sleeved onto the ends of the bottom bracket bearing axle 11,
and then fixedly secured to the bottom bracket bearing axle 11 by a
respective lock pin 24 to secure the wheel boards 21 to the chain wheel 20
and the bottom bracket bearing axle 11. Two semi-circular flat-plate
counter weights 22 are respectively reversely fastened to the wheel boards
21 at an outer side. Each flat-plate counter weight 22 has a coupling hole
220 near the periphery. Two pedal assemblies 25 are respectively coupled
to the flat-plate counter weights 22. Each pedal assembly 25 comprises a
crank 252, and a pedal 253 mounted on one end of the crank 252. The crank
252 of each pedal assembly 25 has a coupling block 250 at one end remote
from the pedal 253, and three mounting lugs 251 equiangularly spaced
around the coupling block 250. The coupling blocks 250 of the cranks 252
of the pedal assemblies 25 are respectively inserted into the coupling
holes 220 on the flat-plate counter weights 22, then the mounting lugs 251
are fixedly fastened to the flat-plate counter weights 22 by for example
screws. Because the pedal assemblies 25 are respectively coupled to the
wheel boards 21 through the flat-plate counter weights 22 at eccentric
locations, the wheel boards 21 can be turned with less effort. Because the
wheel boards 21 are fixedly secured to the bottom bracket bearing axle 11,
the chain wheel 20 is rotated to turn the chain 14 when the user pedals
the pedal assembly 25 to turn the wheel boards 21 and the bottom bracket
bearing axle 11.
Referring to FIG. 5, when a force F is applied to the pedal 253 of one
pedal assembly 25, thus:
1. Because moment of force=force F.times.arm of force, prolonging the arm
of force relatively increases the moment of force. The length L2 of the
crank 252 is fixed. However because the crank 252 is coupled to the wheel
board 21 at an eccentric location, there is a distance L1 between the
central axis of the bottom bracket bearing axle 11 and the connecting
point between the crank 252 and the wheel board 21. Therefore, the arm of
force=L1+L2. Because the arm of force is longer than the length of the
crank 252, less effort is needed to rotate the wheel board 21.
2. Because velocity V=radius of gyration R.times.angular velocity .OMEGA.,
velocity V is relatively increased when the radius of gyration R is
increased and the angular velocity .OMEGA. is remained unchanged. Because
the distance between the pedal 253 and the bottom bracket bearing axle 11
is L1+L2, the radius of gyration R is relatively increased, in consequence
velocity V is relatively increased.
Furthermore, when the crank 253 is turned downwards from the up stroke to
the down stroke, the flat-plate counter weight 22 accelerates the speed of
rotation of the wheel board 21.
While only one embodiment of the present invention has been shown and
described, it will be understood that various modifications and changes
could be made thereunto without departing from the spirit and scope of the
invention disclosed.
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